A trocar assembly is a surgical instrument that is used to gain access to a body cavity. A trocar assembly generally comprises two major components, a trocar tube and an obturator. The trocar tube is inserted through the skin to access a body cavity through the tube in which laparoscopic or arthroscopic surgery and endoscopic procedures are to be performed. In order to penetrate the skin, the distal end of the trocar tube is placed against the skin and an obturator is inserted through the tube. The obturator has a sharp point or cutting edge at its distal end. By applying pressure against the proximal end of the obturator, the sharp point is forced through the skin until it enters the body cavity. The trocar tube is inserted through the perforation made by the obturator and the obturator is withdrawn, leaving the trocar tube as an accessway to the body cavity. Examples of trocar assembly devices are disclosed in U.S. Pat. No. 4,535,773.
The proximal end portion of the trocar tube is typically adjoined by a housing that defines a chamber having an open distal end portion that communicates with the interior lumen defined by the trocar tube. An obturator and other surgical implements or tools axially extend into and are withdrawn from the trocar tube through the distal end portion of the chamber. It is the present practice to provide the chamber with a sealing means, such as a sealing grommet or gasket, through which the obturator or other implements extend. The sealing means seals against the outer surface of the inserted implement and thereby prevents fluids from leaving or entering the body cavity through the trocar tube. The range over which current sealing means effectively operate to seal against implements of different outside diameters is approximately .+-.1 mm. Accordingly, it is frequently necessary to utilize different size trocar tubes during a medical procedure to accommodate implements and tools of different diameters.
There is a need for a trocar assembly that includes a sealing means that is compatible with the expanding number of different size implements and tools that are required during a medical procedure. The typical range of the outside diameter of such implements and tools is from about 2 mm to about 12 mm. A trocar assembly that covers this size range of implements would minimize surgeon adjustments, saving time and reducing the number of trocar tubes required during a medical procedure.
It is also desirable for the sealing means to function during off-center insertion of an implement having sharp edges, such as clip appliers, or when an implement is moved radially after insertion. It is further desirable that the sealing means facilitate the insertion or removal of implements and the removal of tissue therethrough.